1. Field of the Invention
The present invention relates to an on-vehicle electronic control unit that includes a microprocessor and an AD converter and controls an engine of vehicles, and that improves the reduction of control accuracy resulted from fluctuations in constant voltage output voltages due to temperature change of a constant voltage power supply circuit section serving to supply a reference voltage of an AD converter.
2. Description of the Related Art
According to the Japanese Patent Publication (unexamined) No. 218547/1995 (FIG. 1, Summary, Paragraph 0004) “Signal Measuring Device”, a signal measuring device is proposed. This signal measuring device includes: input detection means for detecting inputs of an measured signal; analog/digital conversion means for performing analog-digital conversion of the above-mentioned measured signals to generate measurement data; storage means for storing the above-mentioned measurement data; and calibration signal generation means for generating-calibration signals; the signal measuring device being characterized in that upon storing the above-mentioned storage data, the above-mentioned calibration signals are measured to obtain measurement characteristic error of the signal measuring device, and error of the above-mentioned measurement data is calibrated using the foregoing measurement error. In this signal-measuring device, a concept of executing error compensation at the time of each measurement with the use of a temperature sensor is shown.
Further, according to the Japanese Patent Publication (unexamined) No. 177700/1996 (FIG. 2, Summary) “Electronic Control Unit of Engine”, the following electronic control unit of engines is proposed. This electronic control unit includes a microcomputer that carries out overall control of driving an engine and peripheral devices thereof, and a load-driving transistor that drives loads based on a driving command to be outputted from this microcomputer. The electronic control unit is provided with ambient temperature monitoring means for monitoring an ambient temperature of mentioned load driving transistor, and current-carrying period limiting means for limiting the lower limit of a current-carrying period to this transistor when the foregoing ambient temperature to be monitored or a value equivalent thereto becomes not less than a predetermined limit value. For example, to prevent overheat of a transistor for driving an engine ignition coil, this known art discloses means for carrying out fuel-cut operation or suppression of an intake throttle valve opening.
According to the Japanese Patent Publication (unexamined) No, 121227/1996 (FIG. 2, Summary) “Electronic Control Unit of Engine”, the following electronic control unit is proposed. This electronic control unit includes a transistor that drives an inductance load in synchronization with the rotation of an engine, and a Zener diode that is connected to this transistor to do arc-extinguishing of a fly-back voltage generated at OFF time of mentioned load. The electronic control unit is provided with temperature monitoring means for monitoring a temperature of the mentioned transistor or an ambient temperature thereof, and engine speed limiting means for limiting an engine speed when this temperature to be monitored or a value equivalent thereto comes to be not less than a predetermined limit value. For example, to prevent overheat of a transistor for driving a fuel injection solenoid valve, this known art discloses means for carrying out fuel-cut operation or suppression of an intake throttle valve opening.
Furthermore, according to the Japanese Patent Publication (unexamined) No, 160367/1995 (FIG. 1, Summary) “CPU Heat Generation Suppression Device”, a CPU heat generation suppression device is disclosed. This CPU heat suppression device includes a temperature sensor that measures temperatures of a CPU, a clock frequency determination section that determines an optimum clock frequency to be input to the mentioned CPU based on information from mentioned temperature sensor, and a clock frequency alternation section that causes a clock frequency to be the clock frequency having been obtained in the mentioned clock frequency determination section.